html,
body {
  height: 100%;
}
body {
  display: flex;
  align-items: center;
  padding-top: 40px;
  padding-bottom: 40px;
  background-color: #f5f5f5;
}
  #main-container {
    max-width: 1200px;
    display: flex;
    flex-direction: column;
  }